This invention relates to a MIS (Metal Insulator Semiconductor) structure having a photosensor function which uses silicon carbide (SiC) single crystal.
Silicon carbide has a wide forbidden band (2.2-3.3 eV) and is thermally, chemically and mechanically very stable and further resistant to radiation damages. Therefore, semiconductor elements which use silicon carbide maybe applied in a wide range of applications under severe conditions such as under high temperature, and high output, high levels of radiation conditions in which conventional semiconductor elements using silicon (Si) or the like are difficult to be used.
In recent years, a method of growing silicon carbide single crystal of the 3C type (.beta. type) having an excellent quality and a larger area provided on a Si single crystal substrate has been developed by using the vapor growth method (CVD method) (Japanese Patent Application No. Sho 58-76842 published on Nov. 17, 1988). Further, a method of growing SiC single crystal has been developed in which a surface of the Si substrate is carbonized by heating the substrate in an atmosphere of hydrocarbon gas to produce a silicon carbide thin film thereon. Thereby the SiC single crystal is grown by the CVD method. This method has become the well-known art. In addition, reports on MOS (Metal Oxide Semiconductor) FET prototypes using a SiC single crystal thermal oxidation film have been announced. However, a silicon dioxide (SiO.sub.2) film obtained from the thermal-oxidation of silicon carbide does not generally have good insulation characteristics and the interfacial state density between the silicon carbide and the silicon dioxide is large. Therefore, good characteristics of the elements have not yet been obtained. In order to solve these problems, a method of depositing an amorphous silicon carbide (SiC) film as an insulator has been developed (Japanese Patent Application No. Sho 62-105613published on Nov. 9, 1984). This amorphous SiC film has developed good insulation resistance in the dark and has provided photoconductivity from light illumination.